Mill



Nov. 6, 1928.

C. G. WILLARD MILL Filed June 10, 1927 2 SheetsSheet Nov. 6, 1928.

C. G. WILLARD MILL 2 Sheets-Sheet "llllll'lllllillllll Filed June 10, 1927 INVENTOR Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

CLARENCE WILLARD, OF DENVER, COLORADO, ASSIGNOR TO THE MINE AND SMELTER SUPPLY COMPANY, OF DENVER, COLORADO, A CORPORATION OF COLORADO.

MILL.

Application filed June 10, 1927. Serial No. 197,798

My invention relates to an improvement in mills of that type employing a rotary barrel or drumwhich contains the material to be reduced and steel. balls, cubes, pebbles, rods,

or other freely movable reducing bodies, and

has for one of its objects the provision of a construction whereby the operation of such mills will be greatly improved.

One of the objects of my invention is the provision of a mill in which the reducing medium employed and the material to be reduced, in addition to their usual cascading movement, are given a lateral movement, this result being obtained without varying the length of the reducing chamber. I also provide in the mill of the present construction means on either or both ends of the mill and extending inwardly and laterally thereof for imparting a more circuitous travel to the balls or other reducing medium than would be obtained otherwise. I also by this construction prevent the reducing medium from traveling in a single path and from becoming wedged against the end of the mill. All of this increases or improves the efliciency of the mill.

A further object of my invention is the provision of a radially disposed means in a mill of the character above referred to, this means extending inwardly and laterally and in the operation of the mill increasing the reducing action thereof, as compared with the reducing action in mills as heretofore constructed. These inwardly and laterally extending radially disposed members are arranged so that a lateral movement is imparted to the mill load, i, e., balls, rods, or other reducing medium to be employed and the material to be reduced, the lateral move ment of the load being increased when the members are applied to both ends of the mill, and if these members are arranged in staggered relation, the results above referred to are obtained without reduction in the length of the reducing chamber. This lateral movement of the load also increases the travel of the load in the operation of the mill and works the same toward the center of the mill, where the reducing action is at the maxi mum. I

In the accompanying drawings, wherein I have illustrated an application of my invention to ball mills,-

Figure 1 is a section taken through the mill of Fig. 2 on the line 11 of Fig. 2, looking in the direction of the arrows;

Fig. 2 is a section taken on the line 2-2 of Fig. 1, looking in the direction of the arrows thereon;

Fig. 3 is a fragmentary part sectional elevational view of the feed end of the mill of Fig. 2;

Fig. 4 is an enlarged view of the discharge end of the mill, showing the construction illustrated in Fig. 1 more in detail and on a larger scale;

Fig. 5 is a section on substantially the lines 55 of Fig. 1 looking in the direction of the arrows; and

Figs. 6, 7 and 8 show amodification.

Referring to the drawings in detail, 1 designates the rotarydrum or barrel of the mill, this barrel being provided with wallliners 2, as is usual, andwith feed head 3 and discharge head 4. The mill may be supported for rotation in trunnions 5 and 6 at the feed and discharge ends, respectively, of the mill. Gear 7 is attached to the mill drum and may be driven from any suitable source of power to rotate the drum.

The mill illustrated is provided adjacent its discharge end with grate sectors 8, dis posed about a central member 8 lying abreast of the hollow discharge trunnion 6, a chamher or space 9 being left between these grate sectors and the discharge head 40f the mill to provide a space for the reception of the reduced material which has passed the grates, this material by continued rotation of the drum flowing out through the hollow trunnion 6 to the extcz'icr "if the mill.

In order that the grate sectors 8 which are disposed vertically with respect to the longitudinal axisof the mill may be removably held in position in the mill, I employ clamp bars IOeXtending radially of the grate, each bar lying between adjacent grate sectors whereby" when the bars 10 are bolted in position by bolts 11 provided for that purpose, the grate sectors will be clamped to each other so as to constitute in effect single con tinuous grate.-

The'reducing chamber of the mill, which I will designate 12, is provided by the space within the drum or barrel 1, and in operation this space is partially filled with steel balls, pebbles, cubes or other reducing media, and the material to be reduced, so that as the mill is rotated in its trunnion bearings, the tumbling about and-cascading ofthese materials will effect by impact and/attrition the. desired reduction.

As I have indicated above, however, I have provided means whereby the reducing action of the mill may be greatly increased w1th0ut increase in the power required for operating the mill and without incurring additional expense by way of increasing the load of ,reducing'inedium. 7 To accomplish this end. in

the embodiment illustrated, the clamp bars 1' 10 are extended inwardly and laterally with respect to the grates 8. These extens ons,

which are designated 13, are shown curved or:

concaved on theside or face 1 acent the grate sectors,,while the remote tace lois convex. It ism be understood, however, that plane surfaces may be employed if des red. The clamp bars extendlaterally lna rearward direction with respect to the-rotation of the mill, and hence that portion 16 thereof immediately at the clamp bar isthe forward or leading portion of theextension, while the rear or trailing edge is 18. The trailing edge 18, whichlies parallel to the'mill head, is spaced an appreciable distance from the grates, and as a consequence, when these improved Clampbars areapplied torl he' mill head, between adjacent sections of gratesectors, it will. be apparent, willbe more fully i pointed out hereinaftenjthat the'load in the mill due to thepassage of the extensions of f the clamp bars throur h it will be caused to engage the upper cur edt'ace 15' of cachet 'hese extensions of the clamp bars, and thereby he deflected,andgradually forcedtoward again picked up by the succcedi extension.

the center of the mil.l,}t l ie material which drops off the trailing edge 18 of each extension falling toward the grate' scctorgto be Clamp bar The extensions of each otthe clamp bars is 3lOV1Cl G(l with perforations designated 19.,

these perforations, as will be explained later,

being somewhat larger than the openings between the bars oi the grate sectors, so as not only. to permit of the passage thcrethrough of material which has been reduced sulliciently, butto permit of the passage of some material which has not yetbeenreduced to .a

point where. it is capable .Of being discharged fl clll jlill e lnlll.' other words, these'perforations enable me to obtain a screeningactionbefore' thematerial reaches the grates,

thereby relieving the grates of vpart of the screening action and hence facilitat dis charge of the-material through the rat-es.

It is obvious from the foregoing the i the "appreciable bodily movement or surge of the whole mass which very materially increasesthe reducing-action.

As ,abovedescribed,the clamp bars lOhave, been extended inwardly and laterally, but

it is to be understood that the' loat deflecting a structure mayftake other forms if desired. For example, the inward and laterally extending deflecting I members n'nght be bolted to the clamp bars instead oiibcing integral therewith, or these memberscouldbe attached to the grates directifdesired. Iris to be understood also that where} my invention is applied to mills in which no grates are en'iployed, the inwardly andlaterally cirtnclfed members can be attached to'the'mill head or ally extended defiectingelmembers disposed. radially ot the endfot the, mill which \will cause the "load to be deflected, toward the center of the mill, to increase the reducing action OIi-the mill. 7

Wl'iile I find a greatly inlthe mill ,operationby, theconstruction so far described, inasmuchas there'is aflconstant rearwardand forward movement of the mill load as well as the movement caused by the rotation of: the mill, yet a still further in crease ,in the mass movement andQhence-in the reducing action is obtained it means-such as now to be deseribed be applied to, the Feed 1 endvas well,

At this end of the mill, I provide sectional of the iliners, these clamp bars being bolted may be held-firmly in position, .yet may-be readily removed for the purpose oi": renewal or repair by merelyuemovingthe clamp bars 21.

p to the end linersif desired flni other words, t'he deslderatum ,1s,;up to this point 111 1 my invention, to providelnwardlyand later increased efiiciency, l

end liners 20,]shoivn held in position by clamp bars,21,-1nterposed between adjacent sections to the'feed head3,. sotthat the feedend liners These clampbars 21 which are dispos d radially are proyided with extensions similar to those with which the elamp'bars 10 at'tlie discharge end of illQ DllllJfi-ITC provided; In other words. each clamp bar 21 is provided with an extension 2Qextending into theinill and curving lateral o, as to. partially overlie f or overlap the/ teed end liners. the upper face "the case of the extensions 13 of the clamp bars of each ofthese extensions being ,CODYQX, -&l1llthe lower or under face being concave and spaced from the innertace of the liner. Asin 10, the leading edge of the extensions 22 is at the clamp bars, so that this edge or face portion of the extension will be the first part of the extensionto enter the load, and as the distance of the extension from the faceof the liners gradually increases, it will be obvious that the mill load will be pushed or le flected laterally. It to be noted that if desired the end liners may be cast with inwardly and laterally extending portions thereon, or they may have such formations bolted thereto, in which event the clamp bars would be dis pensed with and the end liners bolted to the mill head in the usual way. I

The radially disposed clamp bars 21 and hence their extended portions 23 are staggered with respect to the clamp bars and their extensions, so as to prevent a reduction in the length of the reducing chamber of the mill. In other words, the length of the reducing chamber remains constant despite the fact that the load is givena lateral surging motion.

Referring now to the operation of the mill.

the upper part of the mill as shown is assumed to be rotating toward the observer, and it will be seen that with the mill rotating in this direction the leading edge 16 of the extension 13 is the first to enter the load. Consequently,

due to the fact that the face of each extension or deflector in contact with the load is at an angle to the face of the grates, the load in the mill will be forced toward the feed end of the mill. At the same time the material will be partially screened by the openings 19 in the extensions, assuming such openings are employed, the material passing through these openings falling toward the grate sectors into the space between the extensions 13 and the grate sectors. The fines, i. e., the-material whichhasbeen reduced to the desired degree of fineness, will pass through the grates into the space 9, behind. the grates to be lifted as the drum continuesits rotation until it has reached the point where it will flow out through the trunnion 6 to be discharged from the mill, while the screened out oversize will be engaged by succeeding clamp bar extensions or deflectors and forced laterally toward the feed end of the mill away from the grates. The extensions of the clamp bars, therefore, perform a double function, to wit, they ellect lateral movement of the mill load or charge to increase the travel of the charge and hence the reducing action, and prevent building up of the oversize at the inner face of the grates so that the discharge of finished material is expedited.

At the same time that this described movement of the load is taking place, due to the formation of the clamp bars 10, the extensions or deflectors 22on the clamp bars 21 at the feed end of the mill are active, these members, due to the rotation of the mill and due-to the fact that they are staggered with respect to the extensions 13, effecting a movement forward of theload toward the center of the mill, with the result that there is constant movement of the load laterally, portions of the load moving toward the discharge end while other portions at the same time are moving in the opposite direction. Hence I provide for a very much increased travel of the material and the reducing medium in the passage of the material. through the mill over that obtained in mills as heretofore constructed andv obtain proportionate increase in the reducing action and etlicienoy of the mill as a reducing apparatus.

From all of the foregoing it will be appar cut that while I provide means within the The clamp bar extensions also increase the length of cascade and rotation of the reducing mass by keeping the balls massed at the center of the reducing chamber and consequently at a higher point in the center of the reducing chamber.

lVhile I have shown and described a ball mill in connection with my invention, it is to he understood that this application of my invention is merely illustrative and does not in any way limit my invention to such type of mill; It is to bc'understood also that the inward and lateral extensions are effective if applied to either end of the mill only, as distinguished from employing them at both ends.

I11 the illustration of Figs. 6 and 7, I have shown amodification of my invention, in

which I have applied inwardly extending defleeting members 25 to the wall liners 26 of the mill drum, either bolted thereto or cast i11- tegral therewith. These members are inclined with respect to thelongitndinal axis of the mill, and have their leading edges flush with the shell liners while their trailing edges are spaced therefrom. The action of these deflecting members is similar to the action of the deflectors at the ends of the mill, and may be substituted therefor or may be additional thereto.

It is evident that various modifications may be made in the construction above described within the purview of this invention.

What I claim is:

1. A mill comprising a rotary drum or barrel providing a reducing chamber adapted to receive a load of freely movable reducing bodies and material to be reduced, a feed head and a discharge head for said drum or barrel, and means spaced from but adjacent each head of said drum or barrel for effecting later- 11? nievel'nent ofi th'ernflfl load whiie nmintain ing the length? of the"ueducingfchambev.

bars for retaining s'ai d feed head linersin position,- said bars extending inw'al dl y of-the mill beyon'c gfihe' plmie of theimier'facehfi the feed head li n'e'r's and mtemlly with respect t6 said liiirs so as topartially overlie theliners, 3. A'mi'll compris'inga rdtany (11' ;L11'1'1'-0'I' b&1- rel, a 'feed head therefo'r, sectibnal' feed head 'liner'g members for maintaining; said fieed I head li'fiers in pesi-tiomeziid member's extendface'of the feed end linergmnd: at

A mill comprisingim co'l'nb'ina tibn awro-i j tar y dfnnr of'bmle l, it feed head therefor; secfiiofia'l'f eed end linel 's 01 said feed heads;

ing "i n wmrd'ly- ;zmd laterally beyond? the inner N an angle to "the plane of said innerffiace;

4. In a mill the combination orfrmrofiary chuni 'or' ban-e15 av feed headt and: a discharge head therefbr', deflectors within the mill. and 3' agent said heads and staggered with respect to 'e'ach' other and effecting lateral nmvemeni of th'e'reducivng' media therein, said: drmng heads and deflectors providing a reducing chamber ofco'nstant length,

This specification si June51927' e CLARENCE G; WILLARD; 

